PIRSA:12110068

Video URL

https://pirsa.org/12110068

What's an unknown POVM, and what does a two qubit state look like?

Pusey, M. (2012). What's an unknown POVM, and what does a two qubit state look like?. Perimeter Institute for Theoretical Physics. https://pirsa.org/12110068

Pusey, Matthew. What's an unknown POVM, and what does a two qubit state look like?. Perimeter Institute for Theoretical Physics, Nov. 06, 2012, https://pirsa.org/12110068 

          @misc{ scivideos_PIRSA:12110068,
            doi = {10.48660/12110068},
            url = {https://pirsa.org/12110068},
            author = {Pusey, Matthew},
            keywords = {},
            language = {en},
            title = {What{\textquoteright}s an unknown POVM, and what does a two qubit state look like?},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2012},
            month = {nov},
            note = {PIRSA:12110068 see, \url{https://scivideos.org/index.php/pirsa/12110068}}
          }

Matthew Pusey University of York

Talk numberPIRSA:12110068
DOI10.48660/12110068
Source RepositoryPIRSA
Collection
Talk Type Scientific Series

Abstract

If probabilities represent knowledge, what is an "unknown
probability"? De Finetti's theorem licenses the view that it is simply a
convenient metaphor for a certain class of knowledge about a series of
events. There are quantum versions for "unknown states" and "unknown
channels". I will explain how "unknown measurements" can be rehabilitated
too.

I will then move to a totally different topic. The Bloch sphere is handy
for representing qubit states, but the equivalent for two qubits is
15-dimensional! I will advocate instead drawing the set of states that Bob
can steer Alice to, the "steering ellipsoid". I will show how entanglement
and discord look from this perspective, and outline a geometric
classification of separable two qubit states.